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Im�act: Impact 75-4: Settlement and Foundation Movement. The project's <br /> preliminary geotechnica! studies determined that structural laads imposed by <br /> buildings more than approximately three stories in height would likely exceed the <br /> bearing capacity of either frll ar weakly consolidated Bay mud underlying <br /> conventional shaUow foundations. Such buildings would potentially experience <br /> gradual but excessi�e Iong-term tatal and differen#ia1 settlements. <br /> Mitigation: Mitigation '15�. The detailed, design-level geotechnical investigations required <br /> under Mitigatian �5-9 for eacF� project constrtaction phase shall include a <br /> thickness and consolidation analysis of all clay soils underlying praposed building <br /> locations. This analysis shall be sufficient to accurately estimate the rate and <br /> totaf amount of consolidation expected to occur in respanse to building <br /> construction, as we!! as the likely magnitude of differential settlement. Buildi�g <br /> foundations, surFace improvernents, and utility connec#ions shall be designed to <br /> structurally withstand the associated movement, without disrupting either <br /> pedestrian or vehicular oonnections to the building. <br /> The requirement described in Mitigafion 1�-1 for pe�r review of the <br /> recommended design-level geotechnical investigations, as wefl as for certification <br /> by the project ci�il engineer that alf provisions af the investigation have been <br /> incorparatec! inta the praject's design and construction, would also apply to this <br /> mitigation and to all subsequent geatechnical and soils mitigation measures set <br /> #orth in Draft �IR chapter 15 (Geology and Soils). <br /> Finding: Implementation of Mitigation 15-4 wauld reduce the potential cornpressible sail <br /> and settlement impacts to a less-fhan-significanf level. <br /> Facts in 5upport of Finding: Implemen#atian of Mitigation 15-4 wo�ld reduce potential <br /> compressible soil and settlemen# impacts to a less-tha�-significant level by <br /> requiring detailed, site-specific geotechnical investigations and solutions <br /> prepared by a registered engineering geologist or geotechnical engineer, witf� <br /> review and approval authority by the City Engineer. These facts are described in <br /> Draft EIR chapter 15 (Geology and Soils} on pages 15-1 through 15-15, which is <br /> h�reby incorporated by reference. <br /> Impact: Impact 15-5: Expansive Soils. Near-surtace clay soils subjected to seasor�al <br /> cycles of wetting and drying can undergo significant�alume changes, expanding <br /> when wet and shrinking when dry. Structures based in these materials would be <br /> subjected to significant stresses that could destabilize foundations and cause <br /> cracking or heaving of floor slabs and exterior�avements. <br /> Mitigation: MitFgation 15-5. The detaifed, design-leve! geotechnical investigatians reauired <br /> for each project construc#ion phase under Mitigation 15�-1 shall include an <br /> evaluation of the iikely effects af building on expansivs soils and shall <br /> recommend specific measures designed to minimize soil movement andlor <br /> counter its potentially destructive effects. <br /> Finding: Implerraentation of Mitigation 1�-5 would reduce the potentiaf expansive soil <br /> impacts to a Iess�than-sigraificant level. <br /> ATTYIRESD.2$98/PC RE50 RECOMMENDING STRNFORD EIR CERTIFICATIDN <br /> REV:08-25-13 VR <br /> Page 20 of 56 <br />